Rhonda Bye had a lot going for her -- brains, beauty, feisty strength.

Heroin and crack crushed it all.

The narcotics ruined her looks and attention span, snuffing out her potential both as a young clothing model for Nordstrom and as a computer whiz who could fix office network problems. Three years ago, a slave to her heroin addiction, Bye landed on San Francisco's streets as a homeless panhandler.

Still, she refused to give up, fighting her way through a frustrating maze of city social services to get into housing and drug rehabilitation. She shook off her addiction, and in the last couple months she had been talking about retraining to work with computers again.

But it was too late. Drug abuse and the ravages of street life had damaged her kidneys so badly that, in mid-February, doctors told her she would need dialysis for the rest of her life.She missed her treatments three times in a row and went into a coma three weeks ago.

On Wednesday, she died. She was 39.

Bye leaves behind two sons and a daughter -- and a lifetime that her family hopes will be an example, in the harshest way possible, of how drugs and homelessness can destroy a person.

"She is an Exhibit A on what heroin and crack does to someone who is unbelievably beautiful, has the sweetest personality in the world, and is even smart," said Bye's brother, Robert Davis of Everett, Wash. "She could have done so much in life, so much. But drugs. ... It was drugs."Bye lies in the San Francisco General Hospital morgue, the destination of all such indigents who die alone in the city from the ravages of drug abuse. But members of her family, many of whom haven't seen her in years, aren't focusing on that image. They choose to remember her in the days before everything went bad.

"She had such a great smile, back when she had teeth, and such a cute giggle," said her mother-in-law, Kay Vestre of Kent, Wash., who is raising Bye's three children and is a manager for the local child protective services office. "Back before she did drugs, they hired her at my workplace to work on the computer system, and oh, my, was she good. She became a trainer for other technicians."

But that -- like most of the promising things in Bye's life -- was before heroin seized her.Bye was raised in Washington state, by a single mother who struggled on welfare or low-paying jobs for much of her childhood, her brother said, "but she always had the strength and brains to try to make something of herself."

Throughout middle school, she attended Bellevue Modeling Academy and walked the runway showing off clothes for Nordstrom. She pulled A's and B's in school, he said, "and by high school she was probably the most popular, cutest girl in class."

Then she met David Bye, whom as recently as this winter she called "the love of my life and the most interesting guy I ever met." By 17, she had dropped out of high school, and they were married, their first child on the way.

"The two of them just started doing cocaine a bit, and very slowly over the next bunch of years they lost what they had," Davis said. Jobs came and went, but about six years ago heroin had gripped them both, and they wound up on and off the streets. Vestre got custody of their three children -- and three years ago, things exploded out of control.

David Bye shot a man to death in Seattle in a fight over insurance money, and the couple fled toward Mexico. San Francisco police found them huddled in an alleyway, arrested David Bye and extradited him to Washington. His wife was left on the street -- and there she stayed.Over the next year, she became a fixture at the Duboce Street off-ramp from Highway 101, the smiling, gentle woman with the ever-ready sign pleading for "just a little help." With her husband out of the picture for the first time since she was 17 -- he was convicted last year of second-degree murder and is serving 32 years in prison -- she was truly on her own for the first time in her life.

"This is not how I wanted to end up," she said one rainy day in 2004 as she begged in traffic. "I want to set a better example for my kids. All I need is a little more of a chance."

That chance came that year, when city Human Services Director Trent Rhorer struck up a conversation with her as she visited with a Chronicle reporter and photographer. He summoned an outreach worker, who signed her up for housing and rehab appointments.

It proved to be the one spark she needed. Bye followed up her many appointments diligently, and nearly three months later, she had a room in the Elm residential hotel and was firmly on methadone treatment to kick heroin.

"Rhonda struck me as someone who genuinely recognized her plight and really wanted to live a better life," Rhorer said. "She was no dummy. But sometimes the toll of drugs is just too much, and it catches up with you.

"What this tells me is that we have to work even harder to get the chronically homeless inside before this kind of damage sets in so deeply."

Her family hoped that she would learn so much from her street ordeals that she could become a counselor someday. Bye herself held that ambition.

"I know how the whole thing works now," she said one day last month in her hotel room, going over brochures of computer training classes. "Man, I could actually help people avoid the crap I've had to live through. Wouldn't that just be great?"